Marvel .22 lr conversion problem

I have already written about this problem that I can't solve, I imported a Marvel .22 conversion that mounted on two Remington Rands sometimes makes me burst fire... problem that both shoot 45acp without any problem.. I changed the disconnector but nothing changed.. What could I do?

Most likely the issue surrounds the marvel slide fit verses the 45 slides you have. The most common issue is the slide upon recoil doesn't push the disconnector head down far enough to disconnect the sear feet from the angled portion of the disconnector. This leaves the nose nose away from The hammer hooks and the hammer drops.

The thread below describes how the disconnector works while also discussing the "long" EGW sear available from them. Make sure the disconnector has freedom of movement on its slot and the middle finger of the sear spring is not too short causing it to catch the bottom edge of the disconnector and locking it. Removing your grip safety allows you to watch the function of the sear and disconnector while cycling the slide. Given those older WW2 frames other issues could be there from wear( worn pin holes ,etc)

https://forum.m1911.org/showthread.php?17145-EGW-quot-long-quot-disconnector-Why-and-or-when

You might take a look at this document-

Microsoft Word - Marvel Functioning.doc (guntalk-online.com)

Doubling 
With the original units we had a few that would double. The problem was that I had the firing 
pin too close to the face of the breech. This didn't happen often and I believe we have since 
fixed all of those early units. 
If your gun doubles with our unit on the frame but not with the 
1911 slide, 95% of the time it is because the sear is too short (less than .778" OAL). 
Because our slide is traveling so fast it can shake the hammer off of the sear when the slide 
breech hits the barrel face. Replace the sear and it will most likely never happen again. 
If you have any questions, please give us a call; we want everyone to be satisfied with our products

What you're telling me about the disconnector is fine but why does this burst problem only occur with the Kart conversion and not when I shoot the 45acp in both Remington Rands?

What's different ?    The slide. The slide controls the downward and upward movement of the disconnector along with the sear spring. It must push the disconnector down enough for it to clear the sear feet. The slot in the slide allows the sear to move up to contact the sear.
Remove the grip safety so you can see what's going on. Scott raises a good issue if the hammer and sear are the original ones on the pistol. Sears from that era were short to begin with and got shorter as they were modified. Today's sear and hammers are soooo much better.

Insufficient headspace giving a slam fire? The Baikals did that after a lot of use. Can you measure rim thickness and the slide recess? Is there a firing pin dent the same as when fired normally?

I had a marvel on an old colt frame once and had a similar issue. The problem was the conversion slide rode too high on the frame causing the problem you are having. The older guns at this point in time have likely have significantly higher variation than say a modern frame.

Yes I agree with "ciiz1180" what you say about old frames...The problem was the conversion slide rode too high on the frame causing the problem..mine are two old Remington Rand made 1942..

I have mine mounted on a DCM Colt frame and have never had a problem with it but then the Marvel Unit is an earlier model.

I solved the problem for now by using rapid fire 22 lr low velocity

ser2711 wrote:I have already written about this problem that I can't solve, I imported a Marvel .22 conversion that mounted on two Remington Rands sometimes makes me burst fire... problem that both shoot 45acp without any problem.. I changed the disconnector but nothing changed.. What could I do?

Here's what I figured out was my problem:
The slide surface that the disconnector rides on is .015" higher on the AA conversion unit than on the 45 slide.
I simply cut .015" off the top of the disconnector pads (see picture). It's now a dedicated .22.

[quote="Wes Lorenz"][quote="ser2711"]I have already written about this problem that I can't solve, I imported a Marvel .22 conversion that mounted on two Remington Rands sometimes makes me burst fire... problem that both shoot 45acp without any problem..[color=#ff0000] I changed the disconnector but nothing changed[/color].. What could I do?[/quote]
Here's what I figured out was my problem:
The slide surface that the disconnector rides on is .015" higher on the AA conversion unit than on the 45 slide.
I simply cut .015" off the top of the disconnector pads (see picture). It's now a dedicated .22.

[url=https://servimg.com/view/19011581/208][img]https://i.servimg.com/u/f34/19/01/15/81/aa_dis10.jpg[/img][/url][/quote]
EGW makes a long disconnector, by .005. This was enough to solve the same issue for me. If this is not enough extra distance between bottom of sear and the shelf that Wes is pointing to here, then you could do what Wes did.

That corner between the disconnector and sear could be worn round. If your reducing pull weight especially if less weight in applied to the sear when shooting .22LR. You might try loosening the over travel screw to provide more over travel to test the problem. You also stated you fixed the problem using low velocity ammo for rapid fire, am I to assume the problem doesn't happen in slow and timed fire with standard velocity ammo? Seem like the problem I mentioned is happening because you start lowing winger pressure quickly during rapid fire. The rounding would allow the disconnector to wedge between the trigger and sear releasing the hammer. Another issue could be the sear hook is long and when engaging the hammer hooks there is an angle at the point the sear contacts the disconnector creating a slight gap. To add to the issue the speed of the slide being faster due to blow back and made from aluminum could cause the disconnectort to hammer up and wedging between the trigger and sear. My suggestion is to determine the problem rather than change ammo for rapid fire because eventually it will get worse and .45 ammo will start to double. What Wess did could have removed any rounding on the disconnectot corner.